Recent evidence indicates that certain groups of rubber manufacturing workers are at risk for squamous cell skin cancer compared to the industry as a whole. It is known that raw materials containing carcinogenic polycyclic aromatic hydrocarbons (PAHs) are used in rubber manufacturing. These include oils, carbon black, waxes, and solvents. A case-control study is proposed drawing on data from two rubber companies to look for an association between squamous cell carcinoma and exposure to PAHs. The cases are 68 male rubber workers who were located from the tumor registries of the Akron, Ohio hospitals. There will be two control series drawn from cohorts of rubber workers that have been developed by the Occupational Health Studies Group. A first series of four controls will be matched on race, sex and age. A second series of four controls will be matched on race, sex, age, and time in the industry. Identification of jobs with PAH exposure will be made by means of an industrial hygiene survey and company records. This information will be linked to individual workers by means of their personnel files. Each employee will receive a rating of his PAH exposure. Data analysis will consider both the level of exposure and the number of years of exposure. Additional analysis will look for an association between: 1) skin cancer and length of employment in the industry using the first control series only; and 2) skin cancer and work areas where PAHs cannot be implicated. If such associations are found, attempts will be made to suggest causal exposures.